MEXICO CITY, Sept 1 (Reuters) - U.S. Commerce Secretary Wilbur Ross wants more than 70 percent of North American content in vehicles built in the United States, Canada and Mexico under a renegotiated NAFTA trade deal, the head of Canada’s largest private sector union said on Friday.

Jerry Dias, national president of Unifor, told reporters he suggested in a recent meeting with Ross that the level be raised to 70 percent from the current 62.5 percent, and that the U.S. commerce secretary suggested a “more aggressive” level.

Ross has long advocated strengthening the rules of origin for the auto industry as a way to bring back automotive production from Asia and other non-NAFTA countries.

Negotiations to revamp the North American Free Trade Agreement are in their second round this weekend in Mexico City, where rules of origin are expected to be discussed.

U.S. negotiators, however, may not reveal specific rules of origin targets until later rounds, according to auto industry lobbyists.

“In fairness to Wilbur, he was more aggressive than I was,” Dias said of Ross’ desired North American content level.

Dias said he thought that a 70 percent rule would be a step in the right direction for an industry whose jobs have migrated from the United States and Canada to Mexico, and would help shift production of some automotive electronics and other parts from Asia and Europe back to North America.

A spokesman for Ross in Washington could not immediately be reached for comment.

Dias said tougher NAFTA rules of origin would only be a small part of restoring manufacturing jobs, and that far stronger labor standards were needed to boost wages in Mexico that are far below those in the United States and Canada.

He said he agreed with U.S. President Donald Trump’s threat to terminate NAFTA if it cannot be improved enough.

“NAFTA has been a disaster for workers in Canada, Mexico and the United States. So when he threatens to walk away from it, that’s OK. So now we need to reconfigure how we fix things,” he said.

At the same time, Dias said that Trump was “not an ally” of unions, describing him as “batshit crazy.” (Reporting by David Lawder; Editing by Richard Chang)